The role of the Kazakhstan orocline in the late Paleozoic amalgamation of Eurasia

After the 2005 Kashmir earthquake, we mapped surface ground fractures in Tangdhar, Uri, Rajouri and Punch sectors and liquefaction features in Jammu area lying close to the eastern side of the Line of Control (LOC) in Kashmir, India. The NW trending ground fractures occurred largely in the hanging wall zone of the southeastern extension of the causative fault in Tangdhar and Uri sectors. The principal compressive stress deduced from the earthquake induced ground fractures is oriented at N10°, whereas the causative Balakot–Bagh fault strikes 330°. The fault-plane solution indicates primarily SW thrusting of the causative fault with a component of strike–slip motion. The ground fractures reflect pronounced strike–slip together with some tensile component. The Tangdhar area showing left-lateral strike–slip motion lies on the hanging wall, and the Uri region showing right-lateral strike–slip movement is located towards the southeastern extension of the causative fault zone. The shear fractures are related to static stress that was responsible for the failure of causative fault. The tensile fractures with offsets are attributed to combination of both static and dynamic stresses, and the fractures and openings without offsets owe their origin due to dynamic stress. In Punch–Rajouri and Jammu area, which lies on the footwall, the fractures and liquefactions were generated by dynamic stress. The occurrence of liquefaction features in the out board part of the Himalayan range front near Jammu is suggestive of stress transfer  230 km southeast of the epicenter. The Balakot–Bagh Fault (BBF), the Muzaffarabad anticline, the rupture zone of causative fault and the zone of aftershocks — all are aligned in a  25 km wide belt along the NW–SE trending regional Himalayan strike of Kashmir region and lying between the MBT and the Riasi Thrust (Murree Thrust), suggesting a seismogenic zone that may propagate towards the southeast to trigger an earthquake in the eastern part of the Kashmir region.     

The Assessment of Global Surface Temperature Change from 1850s:The C-LSAT2.0 Ensemble and the CMST-Interim Datasets

Based on C-LSAT2.0,using high-and low-frequency components reconstruction methods,combined with observation constraint masking,a reconstructed C-LSAT2.0 with 756 ensemble members from the 1850s to 2018 has been developed.These ensemble versions have been merged with the ERSSTv5 ensemble dataset,and an upgraded version of the CMSTInterim dataset with 5°×5°resolution has been developed.The CMST-Interim dataset has significantly improved the coverage rate of global surface temperature data.After reconstruction,the data coverage before 1950 increased from 78%?81%of the original CMST to 81%?89%.The total coverage after 1955 reached about 93%,including more than 98%in the Northern Hemisphere and 81%?89%in the Southern Hemisphere.Through the reconstruction ensemble experiments with different parameters,a good basis is provided for more systematic uncertainty assessment of C-LSAT2.0 and CMSTInterim.In comparison with the original CMST,the global mean surface temperatures are estimated to be cooler in the second half of 19th century and warmer during the 21st century,which shows that the global warming trend is further amplified.The global warming trends are updated from 0.085±0.004℃(10 yr)^–1and 0.128±0.006℃(10 yr)^–1to 0.089±0.004℃(10 yr)^–1and 0.137±0.007℃(10 yr)^–1,respectively,since the start and the second half of 20th century.     

Relaxation Oscillations in Tidally Evolving Satellites

We study the rotational evolution under tidal torques of axisymmetric natural satellites in inclined, precessing orbits. In the spin- and orbit-averaged equations of motion, we find that a global limit cycle exists for parameter values near the stability limit of Cassini state . The limit cycle involves an alternation between states of near-synchronous spin at low obliquity, and strongly subsynchronous spin at an obliquity near 90°. This dynamical feature is characterized as a relaxation oscillation, arising as the system slowly traverses two saddle-node bifurcations in a reduced system. This slow timescale is controlled by ε, the nondimensional tidal dissipation rate. Unfortunately, a straightforward expansion of the governing equations for small ε is shown to be insufficient for understanding the underlying structure of the system. Rather, the dynamical equations of motion possess a singular term, multiplied by ε, which vanishes in the unperturbed system. We thus provide a demonstration that a dissipatively perturbed conservative system can behave qualitatively differently from the unperturbed system. This revised version was published online in July 2006 with corrections to the Cover Date.     

An observational search for large-scale organization of five-minute oscillations on the Sun

The large-scale solar velocity field has been measured over an aperture of radius 0.8 R on 121 days between April and September, 1976. Measurements are made in the line Fei 5123.730 Å, employing a velocity subtraction technique similar to that of Severny et al. (1976). Comparisons of the amplitude and frequency of the five-minute resonant oscillation with the geomagnetic C9 index and magnetic sector boundaries show no evidence of any relationship between the oscillations and coronal holes or sector structure.     

Validation and Joint Inversion of Teleseismic Waveforms for Earthquake Source Models Using Deep Ocean Bottom Pressure Records: A Case Study of the 2006 Kuril Megathrust Earthquake

The importance of accurate tsunami simulation has increased since the 2004 Sumatra-Andaman earthquake and the Indian Ocean tsunami that followed it, because it is an important tool for inundation mapping and, potentially, tsunami warning. An important source of uncertainty in tsunami simulations is the source model, which is often estimated from some combination of seismic, geodetic or geological data. A magnitude 8.3 earthquake that occurred in the Kuril subduction zone on 15 November, 2006 resulted in the first teletsunami to be widely recorded by bottom pressure recorders deployed in the northern Pacific Ocean. Because these recordings were unaffected by shallow complicated bathymetry near the coast, this provides a unique opportunity to investigate whether seismic rupture models can be inferred from teleseismic waves with sufficient accuracy to be used to forecast teletsunami. In this study, we estimated the rupture model of the 2006 Kuril earthquake by inverting the teleseimic waves and used that to model the tsunami source. The tsunami propagation was then calculated by solving the linear long-wave equations. We found that the simulated 2006 Kuril tsunami compared very well to the ocean bottom recordings when simultaneously using P and long-period surface waves in the earthquake source process inversion.